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looper.rs
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looper.rs
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use crate::{
bitcoin::{BitcoinInterface, BlockChainTip, UTxO},
database::{Coin, DatabaseConnection, DatabaseInterface},
descriptors,
};
use std::{
collections::HashSet,
sync::{self, atomic},
thread, time,
};
use miniscript::bitcoin::{self, secp256k1};
#[derive(Debug, Clone)]
struct UpdatedCoins {
pub received: Vec<Coin>,
pub confirmed: Vec<(bitcoin::OutPoint, i32, u32)>,
pub expired: Vec<bitcoin::OutPoint>,
pub spending: Vec<(bitcoin::OutPoint, bitcoin::Txid)>,
pub expired_spending: Vec<bitcoin::OutPoint>,
pub spent: Vec<(bitcoin::OutPoint, bitcoin::Txid, i32, u32)>,
}
// Update the state of our coins. There may be new unspent, and existing ones may become confirmed
// or spent.
// NOTE: A coin may be updated multiple times at once. That is, a coin may be received, confirmed,
// and spent in a single poll.
// NOTE: Coinbase transaction deposits are very much an afterthought here. We treat them as
// unconfirmed until the CB tx matures.
fn update_coins(
bit: &impl BitcoinInterface,
db_conn: &mut Box<dyn DatabaseConnection>,
previous_tip: &BlockChainTip,
descs: &[descriptors::SinglePathLianaDesc],
secp: &secp256k1::Secp256k1<secp256k1::VerifyOnly>,
) -> UpdatedCoins {
let network = db_conn.network();
let curr_coins = db_conn.coins(&[], &[]);
log::debug!("Current coins: {:?}", curr_coins);
// Start by fetching newly received coins.
let mut received = Vec::new();
for utxo in bit.received_coins(previous_tip, descs) {
let UTxO {
outpoint,
amount,
address,
is_immature,
..
} = utxo;
// We can only really treat them if we know the derivation index that was used.
let address = match address.require_network(network) {
Ok(addr) => addr,
Err(e) => {
log::error!("Invalid network for address: {}", e);
continue;
}
};
if let Some((derivation_index, is_change)) = db_conn.derivation_index_by_address(&address) {
// First of if we are receiving coins that are beyond our next derivation index,
// adjust it.
if derivation_index > db_conn.receive_index() {
db_conn.set_receive_index(derivation_index, secp);
}
if derivation_index > db_conn.change_index() {
db_conn.set_change_index(derivation_index, secp);
}
// Now record this coin as a newly received one.
if !curr_coins.contains_key(&utxo.outpoint) {
let coin = Coin {
outpoint,
is_immature,
amount,
derivation_index,
is_change,
block_info: None,
spend_txid: None,
spend_block: None,
};
received.push(coin);
}
} else {
// TODO: maybe we could try out something here? Like bruteforcing the next 200 indexes?
log::error!(
"Could not get derivation index for coin '{}' (address: '{}')",
&utxo.outpoint,
&address
);
}
}
log::debug!("Newly received coins: {:?}", received);
// We need to take the newly received ones into account as well, as they may have been
// confirmed within the previous tip and the current one, and we may not poll this chunk of the
// chain anymore.
let to_be_confirmed: Vec<bitcoin::OutPoint> = curr_coins
.values()
.chain(received.iter())
.filter_map(|coin| {
if coin.block_info.is_none() {
Some(coin.outpoint)
} else {
None
}
})
.collect();
let (confirmed, expired) = bit.confirmed_coins(&to_be_confirmed);
log::debug!("Newly confirmed coins: {:?}", confirmed);
log::debug!("Expired coins: {:?}", expired);
// We need to take the newly received ones into account as well, as they may have been
// spent within the previous tip and the current one, and we may not poll this chunk of the
// chain anymore.
// NOTE: curr_coins contain the "spending" coins. So this takes care of updating the spend_txid
// if a coin's spending transaction gets RBF'd.
let expired_set: HashSet<_> = expired.iter().collect();
let to_be_spent: Vec<bitcoin::OutPoint> = curr_coins
.values()
.chain(received.iter())
.filter_map(|coin| {
// Always check for spends when the spend tx is not confirmed as it might get RBF'd.
if (coin.spend_txid.is_some() && coin.spend_block.is_some())
|| expired_set.contains(&coin.outpoint)
{
None
} else {
Some(coin.outpoint)
}
})
.collect();
let spending = bit.spending_coins(&to_be_spent);
log::debug!("Newly spending coins: {:?}", spending);
// Mark coins in a spending state whose Spend transaction was confirmed as such. Note we
// need to take into account the freshly marked as spending coins as well, as their spend
// may have been confirmed within the previous tip and the current one, and we may not poll
// this chunk of the chain anymore.
let spending_coins: Vec<(bitcoin::OutPoint, bitcoin::Txid)> = db_conn
.list_spending_coins()
.values()
.map(|coin| (coin.outpoint, coin.spend_txid.expect("Coin is spending")))
.chain(spending.iter().cloned())
.collect();
let (spent, expired_spending) = bit.spent_coins(spending_coins.as_slice());
let spent = spent
.into_iter()
.map(|(oupoint, txid, block)| (oupoint, txid, block.height, block.time))
.collect();
log::debug!("Newly spent coins: {:?}", spent);
UpdatedCoins {
received,
confirmed,
expired,
spending,
expired_spending,
spent,
}
}
#[derive(Debug, Clone, Copy)]
enum TipUpdate {
// The best block is still the same as in the previous poll.
Same,
// There is a new best block that extends the same chain.
Progress(BlockChainTip),
// There is a new best block that extends a chain which does not contain our former tip.
Reorged(BlockChainTip),
}
// Returns the new block chain tip, if it changed.
fn new_tip(bit: &impl BitcoinInterface, current_tip: &BlockChainTip) -> TipUpdate {
let bitcoin_tip = bit.chain_tip();
// If the tip didn't change, there is nothing to update.
if current_tip == &bitcoin_tip {
return TipUpdate::Same;
}
if bitcoin_tip.height > current_tip.height {
// Make sure we are on the same chain.
if bit.is_in_chain(current_tip) {
// All good, we just moved forward.
return TipUpdate::Progress(bitcoin_tip);
}
}
// Either the new height is lower or the same but the block hash differs. There was a
// block chain re-organisation. Find the common ancestor between our current chain and
// the new chain and return that. The caller will take care of rewinding our state.
log::info!("Block chain reorganization detected. Looking for common ancestor.");
if let Some(common_ancestor) = bit.common_ancestor(current_tip) {
log::info!(
"Common ancestor found: '{}'. Starting rescan from there. Old tip was '{}'.",
common_ancestor,
current_tip
);
TipUpdate::Reorged(common_ancestor)
} else {
log::error!(
"Failed to get common ancestor for tip '{}'. Starting over.",
current_tip
);
new_tip(bit, current_tip)
}
}
fn updates(
bit: &impl BitcoinInterface,
db: &impl DatabaseInterface,
descs: &[descriptors::SinglePathLianaDesc],
secp: &secp256k1::Secp256k1<secp256k1::VerifyOnly>,
) {
let mut db_conn = db.connection();
// Check if there was a new block before updating ourselves.
let current_tip = db_conn.chain_tip().expect("Always set at first startup");
let latest_tip = match new_tip(bit, ¤t_tip) {
TipUpdate::Same => current_tip,
TipUpdate::Progress(new_tip) => new_tip,
TipUpdate::Reorged(new_tip) => {
// The block chain was reorganized. Rollback our state down to the common ancestor
// between our former chain and the new one, then restart fresh.
db_conn.rollback_tip(&new_tip);
log::info!("Tip was rolled back to '{}'.", new_tip);
return updates(bit, db, descs, secp);
}
};
// Then check the state of our coins. Do it even if the tip did not change since last poll, as
// we may have unconfirmed transactions.
let updated_coins = update_coins(bit, &mut db_conn, ¤t_tip, descs, secp);
// If the tip changed while we were polling our Bitcoin interface, start over.
if bit.chain_tip() != latest_tip {
log::info!("Chain tip changed while we were updating our state. Starting over.");
return updates(bit, db, descs, secp);
}
// The chain tip did not change since we started our updates. Record them and the latest tip.
// Having the tip in database means that, as far as the chain is concerned, we've got all
// updates up to this block. But not more.
db_conn.new_unspent_coins(&updated_coins.received);
db_conn.remove_coins(&updated_coins.expired);
db_conn.confirm_coins(&updated_coins.confirmed);
db_conn.spend_coins(&updated_coins.spending);
db_conn.unspend_coins(&updated_coins.expired_spending);
db_conn.confirm_spend(&updated_coins.spent);
if latest_tip != current_tip {
db_conn.update_tip(&latest_tip);
log::debug!("New tip: '{}'", latest_tip);
}
log::debug!("Updates done.");
}
// Check if there is any rescan of the backend ongoing or one that just finished.
fn rescan_check(
bit: &impl BitcoinInterface,
db: &impl DatabaseInterface,
descs: &[descriptors::SinglePathLianaDesc],
secp: &secp256k1::Secp256k1<secp256k1::VerifyOnly>,
) {
log::debug!("Checking the state of an ongoing rescan if there is any");
let mut db_conn = db.connection();
// Check if there is an ongoing rescan. If there isn't and we previously asked for a rescan of
// the backend, we treat it as completed.
// Upon completion of the rescan from the given timestamp on the backend, we rollback our state
// down to the height before this timestamp to rescan everything that happened since then.
let rescan_timestamp = db_conn.rescan_timestamp();
if let Some(progress) = bit.rescan_progress() {
log::info!("Rescan progress: {:.2}%.", progress * 100.0);
if rescan_timestamp.is_none() {
log::warn!("Backend is rescanning but we didn't ask for it.");
}
} else if let Some(timestamp) = rescan_timestamp {
log::info!("Rescan completed on the backend.");
// TODO: we could check if the timestamp of the descriptors in the Bitcoin backend are
// truly at the rescan timestamp, and trigger a rescan otherwise. Note however it would be
// no use for the bitcoind implementation of the backend, since bitcoind will always set
// the timestamp of the descriptors in the wallet first (and therefore consider it as
// rescanned from this height even if it aborts the rescan by being stopped).
let rescan_tip = match bit.block_before_date(timestamp) {
Some(block) => block,
None => {
log::error!(
"Could not retrieve block height for timestamp '{}'",
timestamp
);
return;
}
};
db_conn.rollback_tip(&rescan_tip);
db_conn.complete_rescan();
log::info!(
"Rolling back our internal tip to '{}' to update our internal state with past transactions.",
rescan_tip
);
updates(bit, db, descs, secp)
} else {
log::debug!("No ongoing rescan.");
}
}
// If the database chain tip is NULL (first startup), initialize it.
fn maybe_initialize_tip(bit: &impl BitcoinInterface, db: &impl DatabaseInterface) {
let mut db_conn = db.connection();
if db_conn.chain_tip().is_none() {
// TODO: be smarter. We can use the timestamp of the descriptor to get a newer block hash.
db_conn.update_tip(&bit.genesis_block());
}
}
fn sync_poll_interval() -> time::Duration {
// TODO: be smarter, like in revaultd, but more generic too.
#[cfg(not(test))]
{
time::Duration::from_secs(30)
}
#[cfg(test)]
time::Duration::from_secs(0)
}
/// Main event loop. Repeatedly polls the Bitcoin interface until told to stop through the
/// `shutdown` atomic.
pub fn looper(
bit: sync::Arc<sync::Mutex<dyn BitcoinInterface>>,
db: sync::Arc<sync::Mutex<dyn DatabaseInterface>>,
shutdown: sync::Arc<atomic::AtomicBool>,
poll_interval: time::Duration,
desc: descriptors::LianaDescriptor,
) {
let mut last_poll = None;
let mut synced = false;
let descs = [
desc.receive_descriptor().clone(),
desc.change_descriptor().clone(),
];
let secp = secp256k1::Secp256k1::verification_only();
maybe_initialize_tip(&bit, &db);
while !shutdown.load(atomic::Ordering::Relaxed) || last_poll.is_none() {
let now = time::Instant::now();
if let Some(last_poll) = last_poll {
let time_since_poll = now.duration_since(last_poll);
let poll_interval = if synced {
poll_interval
} else {
// Until we are synced we poll less often to avoid harassing bitcoind and impeding
// the sync. As a function since it's mocked for the tests.
sync_poll_interval()
};
if time_since_poll < poll_interval {
thread::sleep(time::Duration::from_millis(500));
continue;
}
}
last_poll = Some(now);
// Don't poll until the Bitcoin backend is fully synced.
if !synced {
let progress = bit.sync_progress();
log::info!(
"Block chain synchronization progress: {:.2}% ({} blocks / {} headers)",
progress.rounded_up_progress() * 100.0,
progress.blocks,
progress.headers
);
synced = progress.is_complete();
if !synced {
continue;
}
}
updates(&bit, &db, &descs, &secp);
rescan_check(&bit, &db, &descs, &secp);
}
}